This application relates in general to a method for forming a resin binder system and more preferably to a method for forming a resin binder system of a furfural-phenolic resin system.
Furan modified phenolics have found great favor recently, largely because of their capability of providing high carbon content, high strength and thermosetting characteristics. However, because of the liquid nature of such furan phenolics, difficulties in their use were presented. For example, mixing with sand to form a foundry shape produced a heavy, sticky or viscous mix which was hard to work with. Mixing with carbon for subsequent molding or extrusion produced a sticky mix with little green strength.
Attempts to solve the above problem to render furan modified phenolics more acceptable for use with refractory materials in forming desired shapes and articles, as typified by U.S. Pat. No. 4,051,301 to Laitar, have resulted in a solid thermoplastic resin which, when added to a refractory material such as sand, had to be heated or otherwise dissolved to result in a free-flowing particulate mix that can be converted to a hard rigid thermoset article. However, this desirable end result is achievable only through the use of an expensive formulation procedure, thereby putting the resin in an unfavorable economic position with traditional phenolic novolaks.